Sign up to receive free email alerts when patent applications with chosen keywords are publishedSIGN UP

Abstract:

A driver type golf club head comprising a body having a face, a crown and
a sole, wherein the highest point of the crown surface is located within
a crown apex zone, and a portion of the crown contour exists above a
radius arc of approximately 5.25 inches.

Claims:

1. A driver type golf club head comprising: a body having a face, a crown
and a sole; wherein the highest point of the crown surface is located
within a crown apex zone; and a portion of the crown contour existing
above a radius arc of approximately 5.25 inches.

2. The method according to claim 1 wherein the driver type golf club head
has a volume of less than 400 cubic centimeters.

3. The method according to claim 1 wherein the body is composed of a
stainless steel material.

4. The method according to claim 1 wherein the sole is composed of a
metal material and the crown is composed of a non-metal material.

5. The method according to claim 1 wherein the body is composed of a
titanium alloy material.

6. A driver type golf club head comprising: a body having a face, a crown
and a sole; wherein the highest point of the crown surface is located
within a crown apex zone; wherein the sole is composed of a metal
material and the crown is composed of a non-metal material; and a portion
of the crown contour existing above a radius arc of approximately 5.25
inches.

[0004] The present invention relates to a method for reducing the effects
of drag force when using a driver.

[0005] 2. Description of the Related Art

[0006] The prior art discloses various designs to reduce the drag force to
improve driver performance.

[0007] The prior art fails to provide a driver with designs that
efficiently reduce drag forces and consequentially enable the driver to
be swung faster along its path and contribute to an improved impact event
with the golf ball.

[0008] The United States Golf Association (USGA) has increasingly limited
the performance innovations of golf clubs, particularly drivers.
Recently, the USGA has limited the volume, dimensions of the head, such
as length, width, and height, face compliance, inertia of driver heads
and overall club length. Current methods previously used to improve the
performance of a driver have been curtailed by limitations on design
parameters set by the US GA. An area of driver performance improvement
that exists, as of this date, is the potential to reduce the drag force
that opposes the driver's travel through the air during its path to the
golf ball on the tee. A reduction in drag force would allow the driver
club head to travel faster along its path and contribute to an improved
impact event with the golf ball, resulting in higher golf ball velocities
and consequentially, in longer golf shots.

[0009] The purpose of this invention is to effectively incorporate several
design features in the driver club head that will enable lower drag
coefficients as the driver is swung by a golfer. The design features will
reduce drag forces and consequently allow the driver to be swung faster
than conventional driver designs that currently exist. By improving the
drag coefficients of the crown and sole surfaces and lowering the overall
drag forces that impede the driver club head from moving faster through
the air, the head speed of the driver is increased by approximately 1 to
3 mph.

[0010] The recent past has shown that driver designs have trended to
include characteristics to increase the driver's inertia values to help
off-center hits go farther and straighter. Driver designs have also
recently included larger faces, which may help the driver deliver better
feeling shots as well as shots that have higher ball speeds if hit away
from the face center. However, these recent trends may also be
detrimental to the driver's performance due to the head speed reductions
that these design features introduce due to the larger geometries. The
design of the present invention allows for higher inertias and robust
face design of current drivers in addition to a driver design that will
lower the drag forces on the club head and improve drag coefficients on
the face, sole, and crown surfaces.

BRIEF SUMMARY OF THE INVENTION

[0011] The main objective of the present invention is to improve the
aspect ratio of the driver club head and to improve driver club head
crown surface design. To improve the aspect ration of the driver club
head, a driver is created which has an increased depth, distance from the
face to the most rearward point, while reducing the overall height. This
design will improve air flow over the face and crown of the driver and
minimize the overall projected area of the club head in the direction of
the air flow. Improvements on the driver club head crown surface design
include creating a driver having a crown surface that is flatter, less
curvature, while combining it with an apex point location that is further
away from the face to promote a more preferred air flow over the club
head.

[0012] One aspect of the golf club head of the present invention is a
driver type golf club head comprising a body having a face, a crown and a
sole, wherein the highest point of the crown surface is located within a
crown apex zone, and a portion of the crown contour existing above a
radius arc of approximately 5.25 inches.

[0013] Having briefly described the present invention, the above and
further objects, features and advantages thereof will be recognized by
those skilled in the pertinent art from the following detailed
description of the invention when taken in conjunction with the
accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0014] FIG. 1 is a perspective view of a golf club head superimposed on a
cartesian coordinate system according to a method for designing a golf
club head.

[0015]FIG. 2 is a perspective view of a golf club head placed into a
cartesian coordinate system showing the largest tangent circle method
according to a method for designing a golf club head.

[0016] FIG. 3 is a perspective view of a golf club head superimposed on a
cartesian coordinate system according to a method for designing a golf
club head.

[0017] FIG. 4 is a 2D cross sectional view showing the endpoint of
intersection of a golf club head.

[0018] FIG. 5 is a 2D cross sectional view showing the crown apex zone of
a golf club head.

[0020] FIG. 7 is a 2D cross sectional view of a golf club in the prior
art.

[0021] FIG. 8 is a 2D cross sectional view of an alternative golf club in
the prior art.

[0022] FIG. 9 is a 2D cross sectional view of a second alternative golf
club in the prior art.

DETAILED DESCRIPTION OF THE INVENTION

[0023] The present invention relates to the design relationships and
methods of measurement comprising the improved aspect ratio of the driver
golf club head 20 and the improved driver golf club head 20 crown 26
surface design. To verify the existence of conforming or non-conforming
geometries of a driver club head 20, a method of measurement has been
developed called the, "Largest Tangent Circle Method (LTCM)" 50.

[0024] A driver type golf club head 20 of the present invention comprises
a body 22 having a face 30, a crown 26 and a sole 28, wherein the highest
point, or apex point 46, of the crown 26 surface is located within a
crown apex zone 42, and a portion of the crown 26 contour exists above a
radius arc of approximately 5.25 inches.

[0025] Preferably, the driver type golf club head 20 has a volume of less
than 400 cubic centimeters. In one embodiment, the sole 28 is composed of
a metal material and the crown 26 is composed of a non-metal material.
Preferably, the body 22 is composed of a stainless steel material.
Alternatively, the body22 is composed of a titanium alloy material.

[0026] The LTCM 50 orientation is achieved by bringing the golf club head
20 into a Cartesian Coordinate System (CCS) space where three
perpendicular planes exist. The point at which all three planes intersect
each other is called the origin point. The resulting lines of
intersection of the three planes with each other are perpendicular lines
representing the CCS, with each line or axis being labeled appropriately
X, Y, and Z and pass through the origin point. The values on either side
of the origin of the X, Y, and Z axis are labeled either positive or
negative, as defined and understood in the CCS.

[0027] The driver golf club head 20 is oriented in such a manner such that
the hosel axis line 32 lies in the YZ plane and passes through the origin
point of the CCS.

[0028] The driver golf club head 20 is further oriented such that the
hosel axis line 32 of the golf club head 20 lies at an angle equal to its
designed lie angle from the -Y axis rotating around the origin point
towards the +Z axis, using the right-hand rule with the thumb pointing in
the -X direction.

[0029] As shown in FIG. 1, the golf club head 20 is further oriented by
pivoting it around the hosel axis line 32 until a point or edge on the
sole 28 is tangent to a plane parallel with the XY plane that has the
greatest intersection point value on the Z axis.

[0030] In this embodiment, when the golf club head 20 is viewed along the
X axis, the crown silhouette curve 34 and the sole silhouette curve 36
are projected onto a measurement plane parallel to the YZ plane. A circle
38 is placed on the measurement plane between the projected crown
silhouette curve 34 and the projected sole silhouette curve 36 and is
enlarged until the circle 38 has the maximum diameter possible,
preferably to the nearest 0.001 inch, and is tangent to both the
projected crown silhouette curve 34 and the projected sole silhouette
curve 36. As shown in FIG. 2, a tangent line 40 is created from the
tangent point where the circle touches the projected crown silhouette
curve 34 to the tangent point where the circle touches the projected sole
silhouette curve 36.

[0031] As shown in FIG. 3, a cross sectional curve 44, of the golf club
head 20 is obtained by orienting a plane though the tangent line 40
connecting the tangent points and rotating the plane through the tangent
line 40 so the cross section curve 44 is created with the XY plane that
is parallel with the X axis of the CCS.

[0032] As shown in FIG. 4, the created and oriented plane is used to
intersect the golf club head 20 to obtain 2D cross-sectional views
showing the crown 26 contour of the driver type golf club head 20. An
area encompassed by a rectangle having a preferred height of 0.25 inch
and a preferred length of 1.00 inch, is positioned approximately 0.030
inch above, in the +Z direction, and 0.800 inch to the right, in the +X
direction, of the uppermost intersection curve with the face 30 of the
golf club head 20.

[0033] The rectangular area is an important zone for the crown 26 surface
of the golf club head 20 to have its highest point, apex. It is further
away from the face 30 of the golf club head 20, in the +X direction, and
relatively not too high above the upper edge of the face 30, in the +Y
direction. When the apex of the crown 26 surface falls within this zone,
the airflow moving across the crown 26 surface of the golf club head 20
has been shown to remain laminar and reduce the drag of the driver type
golf club head 20. In addition to the design of the crown 26 surface with
the apex point 46 in the rectangular zone, the flatness of the crown 26
contour and the depth of the golf club head 20 aid in reducing the drag
of the club head 20. It has been shown by Computational Fluid Dynamic
(CFD) studies that the flatter the crown 26 portion of the club head 20,
the longer the airflow across the crown 26 stays attached to the crown 26
without separating and becoming turbulent. Also, the longer the air can
travel along the crown 26 before separating, promotes lower drag forces
are promoted.

[0034] The new methods used to improve aerodynamic properties of a driver
golf club head 20 involve the relationship that the apex point 46 on the
crown 26 surface of a club head 20 has with other geometric features on
the club head 20, such as its depth, height and curvature of the crown 26
surface. The present invention comprises two methods of enhancing the
swing characteristics of a driver club head 20 by reducing the drag
force.

[0035] Method #1). Improved Aspect Ratio of Driver Club Head.

[0036] The method of the present invention involves creating a driver type
golf club head 20 that has an increased depth, distance from the face 30
to the most rearward point, while reducing its height. This improves air
flow over the face 30 and crown 26 of the driver type golf club head 20,
which minimizes the overall projected area of the club head 20 in the
direction of the airflow.

[0037] Method #2). Improved Driver Club head Crown Surface Design.

[0038] An alternative method of the present invention involves creating a
driver type golf club head 20 having a crown 26 surface that is flatter,
combined with an apex point 46 location that is further away from the
face 30 to promote a more preferred air flow over the club head 20.

[0039] Driver type golf club heads 20 created using the methods discussed
enable the golfer to benefit from an improved driver 20 design more
suited to hitting shots with higher ball velocities due to the increased
head speed produced by lower drag forces opposing the driver 20 as it
travels through the air.

[0040] The feature of a flatter crown 26 surface reduces the drag of the
air flow over the crown 26 in a more favorable manner if the of the crown
26 is within the crown apex zone 42 and the crown 26 surface does not
drop off too rapidly. When the apex point 46 is positioned in the crown
apex zone 42, and a flatter crown 26 curvature continues rearward, in the
+X direction, the drag coefficients over the crown 26 surface are reduced
resulting in lower drag forces. In addition, the longer the air flow can
stay attached to the surface of the crown 26, without becoming separated,
the lower the drag forces that are generated. Thus, club head 20 depths
greater than 4.600 inches are preferred.

[0041] In conjunction with reducing the drag coefficient of the crown 26
surface, the projected area of the golf club head 20 is also reduced. The
projected area is a variable in the drag equation, and the lower the
area, the better opportunity exists to lower the overall drag of the club
head 20. By using a club height, h, that is less than half the depth, d,
of the club head 20, a projected area shape that is lower in overall area
and shallower in aspect ratio is achieved in comparison to projected area
shapes of drivers with deeper club heights. This minimizes the
displacement of air molecules as they pass over and around the club head
20. For example if an air molecule hits the center of a driver club 20
face 20, the distance it has to travel up the face 20 and around the club
head 20 is less if the face 30 height is shallower versus the distance it
must travel on deeper face 30 driver 20.

[0042] As shown in FIG. 5, the apex of the crown 26 is located in the
rectangular zone, or crown apex zone 42, and the depth, d, of the club
head 20 must be at least twice the length as the height, h, of the club
head 20 as measured in the plane defined by the LTCM method 50. The
minimum depth, d, of the club head 20 must be equal or greater than 4.600
inch.

[0043] As shown in FIG. 6, using the cross-section of a driver club head
20 derived using the LTCM method with apex of the crown located within
the crown apex zone 42, the crown 26 curve is designed to have some
portion exist above a 5.25 inch radius arc that begins at the apex point
46 of the crown 26 curve and runs towards the back end of the club head
20, in the +X direction.

[0044] In a preferred embodiment, a driver type golf club head 20 formed
using the method of the present invention comprises a body 22 having a
face 30, a crown 26 and a sole 28, wherein the crown 26 is located in a
crown apex zone 42. The club head 20 has a depth, d, the depth being at
least twice the length as a height of the club head, wherein the depth is
at least 4.600 inches.

[0045] The driver type golf club head 20 preferably has a volume of less
than 400 cubic centimeters. The body 22 is preferably composed of a
stainless steel material. The sole 28 is preferably composed of a metal
material and the crown 26 is preferably composed of a non-metal material.
The body 22 is alternatively composed of a titanium alloy material.

[0046] For comparison purposes, FIG. 7-9 show golf club heads in the prior
art, wherein the design features do not comply with the parameters set
forth in the method of the present invention. In FIG. 7, the apex of the
crown is located within the desired crown apex zone 42, the height is
more than 50% of the depth. FIG. 8 shows a golf club head of the prior
art wherein the apex point 46 of the crown does not lie within the crown
apex zone 42. And lastly, FIG. 9 shows an alternative golf club in the
prior art wherein the depth of the club is not equal to or greater than
4.600 inches. [0047] Gibbs, et al., U.S. Pat. No. 7,163,468 is hereby
incorporated by reference in its entirety. [0048] Galloway, et al., U.S.
Pat. No. 7,163,470 is hereby incorporated by reference in its entirety.
[0049] Williams, et al., U.S. Pat. No. 7,166,038 is hereby incorporated
by reference in its entirety. [0050] Desmukh U.S. Pat. No. 7,214,143 is
hereby incorporated by reference in its entirety. [0051] Murphy, et al.,
U.S. Pat. No. 7,252,600 is hereby incorporated by reference in its
entirety. [0052] Gibbs, et al., U.S. Pat. No. 7,258,626 is hereby
incorporated by reference in its entirety. [0053] Galloway, et al., U.S.
Pat. No. 7,258,631 is hereby incorporated by reference in its entirety.
[0054] Evans, et al., U.S. Pat. No. 7,273,419 is hereby incorporated by
reference in its entirety.

[0055] From the foregoing it is believed that those skilled in the
pertinent art will recognize the meritorious advancement of this
invention and will readily understand that while the present invention
has been described in association with a preferred embodiment thereof,
and other embodiments illustrated in the accompanying drawings, numerous
changes, modifications and substitutions of equivalents may be made
therein without departing from the spirit and scope of this invention
which is intended to be unlimited by the foregoing except as may appear
in the following appended claims. Therefore, the embodiments of the
invention in which an exclusive property or privilege is claimed are
defined in the following appended claims.